ISNORMAL(3P)

📦 version 2017a, in alpine 3.22, alpine 3.23, alpine 3.24, arch rolling, nixpkgs unstable, opensuse-leap 16.0

💖 ISNORMAL(3P) 💖

okay bestie, welcome to the POSIX Programmer's Manual ✨ this is isnormal(3P) and it is literally the vibe-check function for floating point numbers. let's get into it 🫶

🌸 PROLOG 🌸

real talk first: this manual page is part of the POSIX Programmer's Manual. the Linux implementation of this interface may differ — so go consult the corresponding Linux manual page for the deets on Linux behavior. or, lowkey, the interface might not even be implemented on Linux at all. 💀

✨ NAME ✨

isnormal — test for a normal value. that's the whole job. icon behavior.

🎀 SYNOPSIS 🎀

#include <math.h>

int isnormal(real-floating x);

💅 DESCRIPTION 💅

so the functionality described on this reference page is aligned with the ISO C standard. if there's any conflict between the requirements described here and the ISO C standard, that conflict is unintentional — not me causing drama. this volume of POSIX.1‐2017 defers to the ISO C standard, periodt. 👑

the isnormal() macro shall determine whether its argument value is normal. and by normal we mean neither zero, subnormal, infinite, nor NaN. it's giving "actually well-behaved number" energy 🌈

here's the order of operations, bestie:

  1. First, an argument represented in a format wider than its semantic type is converted to its semantic type.
  2. Then determination is based on the type of the argument.

that's it. that's the whole algorithm. the way it just... converts and then checks. obsessed. ✨

🦋 RETURN VALUE 🦋

the isnormal() macro shall return a non-zero value if and only if its argument has a normal value. if-and-only-if, bestie — no wiggle room, no gray area, no "it depends". 🎯

🍓 ERRORS 🍓

No errors are defined. nothing. zero. zilch. this function is unbothered, moisturized, in its lane, focused, flourishing. 💅

heads up: the following sections are informative. meaning they're the commentary track, not the actual rules. 📝

🌈 EXAMPLES 🌈

None. 🙈

💜 APPLICATION USAGE 💜

None. 🙈

⭐ RATIONALE ⭐

None. 🙈

🧚 FUTURE DIRECTIONS 🧚

None. 🙈

(three "None"s in a row is honestly such a mood. the standards committee said "no notes". 🎀)

👑 SEE ALSO 👑

  • fpclassify()
  • isfinite()
  • isinf()
  • isnan()
  • signbit()

also! the Base Definitions volume of POSIX.1‐2017, <math.h> — go read that one too, iykyk 📚

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

okay that's the whole page bestie, thanks for reading my TED talk 🫶 and for the sign-off: this lil masterpiece came from IEEE/The Open Group, dated 2017, and it's filed under ISNORMAL(3P). slay, no cap, go check if your floats are normal 💅✨🌸

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